System Metadata

Cloud CMS automatically tracks system metadata for all of the objects that you create within it. System metadata consists of non-data values that describe things like who created an object and when it was modified.

System Metadata

This system metadata is tracked under the special _system key at the root of your objects. This system metadata is read-only in so far as it is tracked by Cloud CMS automatically.

It is available for any object returned by any of the Cloud CMS APIs by simply specifying metadata=true as a request parameter.

System metadata can be used within your queries just like any other key/value pair within your data set. For nodes, system metadata does not participate in schema validation.

Creation

Cloud CMS automatically tracks system metadata around the creation of every object:

Last Edit

In addition to last modification (which includes modifications by any user, including system users), Cloud CMS automatically tracks last intentional modifications by editorial users. This is to say, Cloud CMS separately tracks modification information concerning changes made deliberately by editorial users.

Suppose an editorial user saves a change to a document a 1:00:00 pm. After the save, a rule might trigger that runs an AWS Transcoder job that converts video described by input keys on the document. The resulting output keys would later be written back to the document at, say, 1:02:47 pm. In this case, the editor last modification timestamp would be 1:00:00 pm (because, from the editor's standpoint, that's when they last made a change). However, the modified last modification timestamp would be 1:02:47 pm (because, technically, that's the last moment in time when the document was updated - even if it was by a system process).

Nodes

Content nodes in Cloud CMS also track a few additional system metadata properties. Unlike other objects in Cloud CMS, content nodes are versioned using changesets and so things like changeset IDs and deletion state are captured as system metadata.

Key

Type

Description

_system.deleted

boolean

Whether this node was deleted (written onto its changeset as a delete)

_system.changeset

string

The ID of the changeset upon which this node was written

API

In using the Cloud CMS API, you can request system metadata properties by adding the following to your call:

?metadata=true

System metadata properties will be available under the special _system key. Here is an example: